There are systems, such as synchronous motors and generators, which supply electrical current to a rotor winding by way of slip rings. The current is typically applied to the slip rings via brushes mounted on a fixed conducting ring. Ordinarily, the slip rings in such systems are at low voltage.
A rotary transformer system comprises a rotatable shaft having at least one and preferably plural electrically conductive slip rings mounted thereon. The slip rings of the phase planes are electrically connected to their respective windings on rotor assembly by the bus conductors. The bus conductors extend through respective phase isolated bus ducts formed interiorly in rotatable shaft. The bus ducts have a buffer provided therebetween so that the bus ducts are not in physical contact, but are spaced apart and separated.
A mouth and annulus of each bus duct extend through a cover plate. The cover plate is secured by fasteners through insulated spacers and is held slight aloft above the circumference of rotatable shaft, thereby insulating cover plate from rotatable shaft. The cover plates of adjacent bus ducts are electrically connected by a flux plate. The flux plate extends around the exterior of rotatable shaft and is secured to rotatable shaft by fastener assemblies. Each phase conductor is thus in its own grounded metal enclosure, e.g., bus duct. The isolated phase bus ensures that any fault or electrical failure or arc-over will occur first to ground before becoming a phase to phase fault.